1. Technical Field
This disclosure relates to a liquid ejecting head and a method of manufacturing the same, an image forming apparatus, a liquid drop ejecting device, and a recording method.
2. Description of the Related Art
As an image forming apparatus such as a printer, a facsimile, a copying machine, and a composite machine thereof, for example, an ink jet recording apparatus is known. Such an ink jet recording apparatus conducts recording (for example, image formation, image printing, character printing, and printing may be used as synonyms.) by using a liquid ejecting head as a recording head and by ejecting an ink drop as recording liquid onto a medium to be recorded such as a recording paper (hereinafter, it may be called a “paper sheet”, the material of which is not limited to paper, and it may be also called a recording medium, a transfer paper, a transfer material and a material to be recorded).
Meanwhile, since a liquid ejecting head is of conducting recording by ejecting a liquid drop from a nozzle thereof, the form or precision of the nozzle greatly influences the ink liquid jetting performance. Further, it is known that the properties of the surface of a nozzle forming member for forming a nozzle hole also influences the ink drop jetting performance. For example, when ink adheres to the peripheral portion of the nozzle hole on the surface of the nozzle forming member and ununiform ink pool is formed, it is known that a disadvantage is caused of, for example, bending the direction of ejecting ink, making the sizes of ink drops be ununiform, or making the traveling speed of an ink drop be unstable.
Therefore, in a liquid ejecting head, for example, an ink-repellent layer (film) or a water-repellent layer is generally formed on the surface at the side of liquid drop ejection.
For example, JP-A-2001-232799, JP-A-2003-072085, JP-A-2003-072086, and JP-A-08-025630 disclose the formation of a fluorine-containing water-repellent film, formation of a water-repellent film of hexamethyldisiloxane, etc., by means of plasma polymerization, the formation of a water-repellent film such as fluororesin polymerization films and silicone resin polymerization films, and the formation of a hydrophilic film and water-repellent film, respectively.
Also, as a method for forming a water-repellent film, JP 3379119 discloses a method for applying a water-and-oil-repellent film by dipping the surface of a nozzle into a solution in which a water-and-oil-repellent material is dissolved while a condition of emitting gas from the back side of the nozzle to the surface thereof is maintained and subsequently taking the nozzle surface away from the solution and leaving it while the gas is emitted.
As described above, for a head using a fluororesin for a water-repellent layer, specifically, there is used, for example, a method for forming a thin film of PTFE by subjecting the surface of a metal nozzle plate to eutectoid plating and heating treatment, and a method for applying a fluorine-containing water repellency agent on the surface of a nozzle plate (substrate) made of a metal or a resin.
In the case of such a nozzle forming member whose a water-repellent layer is made of a fluororesin, it is possible to provide a good water repellency (ink repellency) by a publicly known dye ink or pigment ink with a surface tension greater than 30 mN/m.
However, in an experiment conducted by the inventor, it was found that there is a problem of exhibiting no sufficient water repellency (ink repellency) in the case of using an ink with a low surface tension of 30 mN/m or less or an ink containing a fluorine containing compound.
On the other hand, as described above, for a head using a silicone resin coating as a water-repellent film, specifically, there has been applied, for example, a method for vacuum-depositing a liquid silicone resin material or a method for forming a silicone oil by means of plasma polymerization.
However, when such a method for forming a silicone resin coating is used, vacuum processing is needed at the time of film formation, and therefore, the equipment is large which causes the cost to be high. Also, since the time period for film formation is long and a formed coating is very thin in the vacuum deposition and plasma polymerization, a defect such as a pinhole is easily generated. Further, in a method such as vacuum deposition and plasma polymerization, a problem may occur such that it is difficult to thicken the silicone resin coating and it is difficult to keep the sufficient durability of a nozzle surface (the surface of a nozzle forming member at the side of liquid drop ejection) against wiping thereof which is performed in a head maintenance and recovery operation or ink.
Further, as disclosed in JP 3379119 described above, in the method for forming an ink-repellent layer on the surface of a nozzle plate by dipping the nozzle plate into a solution in which a ink repellency agent is dissolved while gas is jetted from a nozzle hole, air bubbles are generated in the solution since the dipping into the solution is made while the gas is jetted. Therefore, when the solution is cured at ordinary temperature, there may be a problem such that it is necessary to leave the solution in the atmosphere and it is difficult to keep the condition of the solution so that the film thickness of an ink repellency layer cannot be controlled due to the change of the solution viscosity.
Herein, the inventor has already invented a method for forming a water-repellent layer by uniformly applying a liquid silicone resin on only a desired portion of the surface of a nozzle forming member using a dispenser. In this case, in order to apply an ordinary temperature-curing type silicone resin, it is necessary to prevent the resin from entering the inside of the nozzle, and therefore, it is necessary to adopt, for example, a countermeasure such that air is jetted from the nozzle to the outside thereof or a removable protecting member is embedded in the nozzle. Accordingly, the simplification of a coating process may become a new problem.
In such a situation, the inventor have found to provide a liquid ejecting head, a method of manufacturing the same, an image forming apparatus, a liquid drop ejecting device, and a recording method, any of which makes it possible to simplify a process for coating with a resin layer.